The semiconductor industry has experienced rapid growth due to continuous improvements in the integration density of a variety of electronic components (e.g., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from repeated reductions in minimum feature size, which allows more components to be integrated into a given area. As the demand for even smaller electronic devices has grown recently, there has grown a need for semiconductor devices having reliable aluminum based interconnection structures.
Aluminum based interconnection structures of a semiconductor device may comprise a plurality of lateral interconnections such as metal lines and a plurality of vertical interconnections such as vias. Various active circuits of the semiconductor may be coupled to external circuits through a variety of conductive channels formed by the vertical and lateral interconnections.
Aluminum based interconnection structures of a semiconductor device can be fabricated using suitable semiconductor fabrication techniques such as etching, Damascene and the like. In an etching based aluminum interconnection fabrication process, an aluminum layer is formed over a semiconductor substrate. According to the pattern of the aluminum interconnection structure, an etching process is applied to the aluminum layer to form a plurality of openings. A dielectric material is filled in the openings to isolate the remaining aluminum layer.
Alternatively, aluminum based interconnection structures may be formed by Damascene processes. Damascene processes can be divided into categories, namely single damascene processes and dual damascene processes. In single damascene technology, a metal via and its adjacent metal line may have different process steps. As a result, each may require a chemical mechanical planarization process to clean the surface. In contrast, in dual damascene technology, a metal via and its adjacent metal line may be formed within a single damascene trench. As a result, one CMP process is required in a dual damascene process to form the metal via and its adjacent metal line.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale.